Re: A way around _HAS_ITERATOR_DEBUGGING

From	Paavo Helde <myfirstname@osa.pri.ee>
Newsgroups	comp.lang.c++
Subject	Re: A way around _HAS_ITERATOR_DEBUGGING
Date	2021-06-02 21:13 +0300
Organization	A noiseless patient Spider
Message-ID	<s98ho9$fke$1@dont-email.me> (permalink)
References	<s97uob$306$1@dont-email.me> <s98238$pm4$1@dont-email.me> <s9848m$9te$1@dont-email.me> <s98ceo$8uk$1@dont-email.me> <s98dai$eqn$1@dont-email.me>

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02.06.2021 19:57 Bonita Montero kirjutas:
>> Says the person who complains that her code does not work in practice 
>> with a widespread implementation, unless specifically silenced with a 
>> _HAS_ITERATOR_DEBUGGING macro (note: using this macro is deprecated by 
>> MS).
> 
> That has nothing to do with pseudo-UB.

There is no such thing as pseudo-UB. If your code contains UB, it might 
work, it might not work, it might appear to work without really working, 
and even if it worked it might cease to work in the next day, next 
compiler, or the next compiler version. There are no guarantees.

A term like "pseudo-UB" implies that there is some magic guarantee that 
the UB code always works as intended. Alas, UB specifically means no 
guarantees, so there is no such thing. Even if you hack your UB code to 
(apparently) work with some specific C++ implementation, you have no 
guarantee that your code will work with any other C++ implementation, or 
with the next version of the same implementation.

The fact that your code does not work with a specific C++ implementation 
without hacking already shows that this is not a theoretical issue.

If the C++ committee comes around and says, yes, sorry, we make 
&*vec.end() defined behavior after all, then yes, you are welcome to 
write this code, now with defined behavior, and MS is obliged to fix 
their now non-conforming compiler. But until this has not happened, UB 
is UB.

Thread

A way around _HAS_ITERATOR_DEBUGGING Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-02 14:49 +0200
  Re: A way around _HAS_ITERATOR_DEBUGGING "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-06-02 15:07 +0200
    Re: A way around _HAS_ITERATOR_DEBUGGING Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-02 15:12 +0200
      Re: A way around _HAS_ITERATOR_DEBUGGING "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-06-02 20:27 +0200
        Re: A way around _HAS_ITERATOR_DEBUGGING red floyd <myob@its.invalid> - 2021-06-02 14:24 -0700
        Re: A way around _HAS_ITERATOR_DEBUGGING Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-03 00:54 +0200
        Re: A way around _HAS_ITERATOR_DEBUGGING Öö Tiib <ootiib@hot.ee> - 2021-06-02 17:30 -0700
  Re: A way around _HAS_ITERATOR_DEBUGGING Paavo Helde <myfirstname@osa.pri.ee> - 2021-06-02 16:46 +0300
    Re: A way around _HAS_ITERATOR_DEBUGGING Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-02 16:23 +0200
      Re: A way around _HAS_ITERATOR_DEBUGGING Paavo Helde <myfirstname@osa.pri.ee> - 2021-06-02 19:43 +0300
        Re: A way around _HAS_ITERATOR_DEBUGGING Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-02 18:57 +0200
          Re: A way around _HAS_ITERATOR_DEBUGGING Paavo Helde <myfirstname@osa.pri.ee> - 2021-06-02 21:13 +0300
            Re: A way around _HAS_ITERATOR_DEBUGGING James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-06-02 17:23 -0400
              Re: A way around _HAS_ITERATOR_DEBUGGING Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-03 00:53 +0200
            Re: A way around _HAS_ITERATOR_DEBUGGING Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-03 00:52 +0200
        Re: A way around _HAS_ITERATOR_DEBUGGING Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-02 18:59 +0200
      Re: A way around _HAS_ITERATOR_DEBUGGING Juha Nieminen <nospam@thanks.invalid> - 2021-06-03 09:21 +0000
        Re: A way around _HAS_ITERATOR_DEBUGGING Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-03 11:33 +0200
          Re: A way around _HAS_ITERATOR_DEBUGGING Bo Persson <bo@bo-persson.se> - 2021-06-03 12:17 +0200
            Re: A way around _HAS_ITERATOR_DEBUGGING Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-03 12:25 +0200
          Re: A way around _HAS_ITERATOR_DEBUGGING Juha Nieminen <nospam@thanks.invalid> - 2021-06-03 17:49 +0000
            Re: A way around _HAS_ITERATOR_DEBUGGING MrSpook_ujp@3p26kggzpvpn2h.gov.uk - 2021-06-04 07:43 +0000
        Re: A way around _HAS_ITERATOR_DEBUGGING James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-06-03 11:06 -0400
          Re: A way around _HAS_ITERATOR_DEBUGGING David Brown <david.brown@hesbynett.no> - 2021-06-03 19:07 +0200
          Re: A way around _HAS_ITERATOR_DEBUGGING Paavo Helde <myfirstname@osa.pri.ee> - 2021-06-03 20:18 +0300
            Re: A way around _HAS_ITERATOR_DEBUGGING Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2021-06-04 10:22 +0100
              Re: A way around _HAS_ITERATOR_DEBUGGING Paavo Helde <myfirstname@osa.pri.ee> - 2021-06-04 14:19 +0300
                Re: A way around _HAS_ITERATOR_DEBUGGING Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2021-06-04 13:07 +0100
            Re: A way around _HAS_ITERATOR_DEBUGGING James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-06-04 10:40 -0400
              Re: A way around _HAS_ITERATOR_DEBUGGING Paavo Helde <myfirstname@osa.pri.ee> - 2021-06-04 19:28 +0300
                Re: A way around _HAS_ITERATOR_DEBUGGING James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-06-04 13:04 -0400
                Re: A way around _HAS_ITERATOR_DEBUGGING "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-06-04 13:30 -0700
                Re: A way around _HAS_ITERATOR_DEBUGGING MrSpook_6qpp@dggw8.org - 2021-06-05 09:28 +0000
                Re: A way around _HAS_ITERATOR_DEBUGGING Paavo Helde <myfirstname@osa.pri.ee> - 2021-06-04 23:45 +0300
          Re: A way around _HAS_ITERATOR_DEBUGGING Juha Nieminen <nospam@thanks.invalid> - 2021-06-03 17:52 +0000

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